We present a case of a 30-month-old child who presented with anemia and acute renal failure, and was found to have bilateral renal involvement by primary cytotoxic T-cell lymphoma. This was characterized by a monotonous interstitial lymphoid infiltrate with extensive necrosis. The tumor cells showed a CD8, granzyme, and TIA1-positive phenotype with no evidence of Epstein-Barr virus by in situ hybridization. The differential diagnosis based on the biopsy findings included a reactive interstitial nephritis; however, molecular studies confirmed T-cell clonality. She was started on induction chemotherapy and subsequently received maintenance therapy with methotrexate and 6-mercaptopurine. The patient had a complete response after chemotherapy and at 21 months of follow-up, she has no evidence of residual lymphoma; however, she has developed a dilated cardiomyopathy and she remains in renal failure. We discuss the morphologic, immunophenotypic, and molecular features of our case and describe the clinical course of our patient. We review the literature on primary renal lymphoma with an emphasis on T-lineage lymphomas and those that occur in children.